Amd vaman r



Patented June 1929.

UNITED STATES PATENT OFFICE.

WILLIAM B. STODDARD, OF STAMFORD, CONNECTICUT, AND VAMAN R. KOKATNUR, OF ARLINGTON, NEW JERSEY, ASSIGNOR-S T0 PILOT LABORATORY, INC., OF ARLINGTON, NEW JERSEY, A CORPORATION OF NEW JERSEY.

PROCESS OF MAKING FATTY-ACID PEROXIDE.

N 0 Drawing.

This invention relates to processes of manufacturing organic peroxides and is particularly adapted to making higher fatty acid peroxides and peroxy compounds.

The fatty acid peroxides and peroxy compounds forming the subject of our invention are admirably suited for bleaching, for use in pharmaceutical preparations and for synthetical purposes; also as bactericidal agents, internal antiseptics, especially in many toilet preparations where the antiseptic residue is desired to be harmless, and in skin bleaching creams where the bleaching agent should be harmless to the skin; also in tooth paste and powders where the bleaching and antiseptic agent used is harmless even if swallowed. For all of these uses, and others, these peroxides are very valuable.

Heretofore the higher fatty acid peroxides or peroxy compounds, such as caproyl, capryl, lauryl, palmityl, oleyl, stearyl, and ricinolyl peroxides and per acids have been unknown. Unlike the peroxides of the lower members of the fatty acid series such as acetyl peroxide, propionyl peroxide, and

, butyryl peroxide, the higher fatty acid peroxides are much more stable with respect to decomposition and hydrolysis and are considerably less explosive than the peroxides of the lower members of the fatty acid series, which new characteristics make these peroxides available for many valuable uses. Almost all known organic peroxides explode either on sudden heating, ignition or on striking. The higher fatty acid peroxides on the other hand burn quietly on ignition and are far less explosive on impact or otherwise. Thus it can be readily seen that these higher fatty acid peroxides have run expected properties as distinguished from organic peroxides heretofore known, and particularly from those of the lower fatty acids.

Ve have discovered that these peroxides can be satisfactorily made by a modification of known methods of producing peroxides such as (1) by the action of metallic peroxides on acid anhydrides or (2) by the action of alkaline hydrogen peroxide on acid chlorids. In making these peroxides by the latter method we have found. that it is particularly advantageous to use strongly alkaline agents such for exam ale as Caustic soda or caustic potash. A1 Taline agents Serial No. 227,855.

have heretofore been used for producing fatty acid peroxides by peroxidizing fatty acid chlorids with hydrogen peroxide, but these alkaline agents have heretofore been used merely to neutralize the hydrochloric acid formed during the reaction. Both strong and weak alkalis have been used for the purpose but merely to neutralize the hydrochloric acid formed in the process, and it has even been. suggested to use weak alkaline agents with definite pH value. We have found however, that weak alkaline agents are not as suitable as strong alkalis for use in the peroxidation of fatty acids. The fatty acid chlorids are unusually stable towards hydrolysis. Consequently weak alkaline agents do not serve to the best advantage in the reaction of fatty acid chlorids with hydrogen peroxide. WVe have found, however, that strong alkalis in suitable concentration are particularly adapted for this purpose and bring'about a quick reaction with nearly quantitative yields. The concentration of caustic alkali in the bath should be not greater than 10 per cent. It should preferably be stronger at the beginning of the reaction, reaching about .4 per cent at the end of the reaction. It is known that strong caustic alkalis react de structively on some organic peroxides and consequently too large an excess and too great a concentration of such reagents should be avoided in order to produce good yields. In making fatty acid peroxides, on the contrary, we have found that an excess of even around 100 per cent of the caustic alkali does not materially affect the yield, if the term perature be regulated and the time of the reaction properly controlled.

A preferred method of producing fatty acid peroxides by our process is as follows:

About 300 litres of water are placed in a reaction vessel fitted-with an efficient agitator. To this are added about 48 litres of a solution containing about 26.3 per cent caustic soda, the agitator started, and sufficient crushed ice added to cool the solution to about 0 G. Then about 168 litres of hydrogen peroxide of about 7 per cent strength are added and followed by more ice. a 1 per cent soapsolution, and finally (3O kilegrains of a fatty acid Chloris. such as 1nd, clinic. or a mixture of tannin:

This is followed by about 25 litres of i oil acid chlorids whose average molecular weight is about 225, is run 1n rapidly with the continued addition of ice at a rate at least suflicient to take up the heat produced by the reaction. The agitation is continued for about 5 to 10 minutes or until the odor of the acid chlorids disappears. More of tl 1 per cent soap solution may be added during the reaction iffound necessary but in no case more than litres all told should be added. The function of the soap solution is to: promote emulsification, thus hastening and promoting the complete formation of the peroxide or mixed peroxides.

The reaction mixture, when made as above, may then be acidified with dilute sulphuric acid and the separated fatty acid peroxide worked up in any desired manner. If a pure peroxide is. desired it may be liltered, washed and dried or melted. It also may be extracted, the extract dried and the solvent removed by evaporation. The pure peroxide obtained in this manner is a white, low-melting solid and has the general appearance of the corresponding fatty acids. Its purity is Very high. It burns without explosion and has a somewhat aromatic odor. 'It is much more stable toward heat and water than most of the organic peroxides heretofore known and does not explode upon strong impact. The pure peroxide is therefore suitable to be handled and used in various arts without danger. Either solid or liquid compositions may be made as de sired. In the example, instead of hydrogen peroxide and caustic soda, a solution of sodium peroxide in an equivalent amount may be used.

Liquid peroxide compositions are particularly advantageous and we have found that they aremore stable and more homogeneous than solid peroxide compositions. As sol vent vehicles which may be used to dissolve the solid fatty acid peroxides to produce liquid compositions, the following may be mentioned: liquid hydrocarbons of petroleum or coal tar origin and some of their derivatives. As examples of such solvents, pentane, decane, kerosene, benzene, xylene, cymene, carbon-tetrachlorid, chlor-benzene, acetone, ethyl acetate, ethylcinnamate, acetic anhydride, anisol, higher ethers and cyclic oxids, may be mentioned. The important point in this connection is that the solvent must be inert, that is, it must be substantially free from any action on the peroxide compound. Liquid compositions may be made far more easily than solid compositions and with the saving of many operations. Thus after acidification a peroxide compound may be directly extracted by a solvent such as above mentioned, water removed and the composition dried by means of suitable drying agents such as anhydrous sodium sulfate or magnesium sulfate.

The liquid peroxide compositions have many advantages over solid peroxide compositions, among which may bementioned greater homogeneity and stability. They can be more easily and uniformly applied in the arts, as they can be (.lissolvcd or suspended in liquids and sprayed on solids. In general they occupy less space than solid compositions and may thus be more easily transported. They save many operations such as filtration, oven drying, grinding, etc., in their preparation.

If acid chlorids of lower molecular weight such as caproyl chlorid or capryllyl chlorid, are used in the process described above proportionately larger or smaller amounts of alkali and hydrogen peroxide may be used as required. The temperature limits for making these peroxides have a. wide range, due to the stability of the peroxides. A range between 1() C. and 50 C. has been found to give good results. If the temperature used is high, then the amount of alkali used should be close to the theoretical amount. If a large excess of alkali is used, both the temperature and time' of reaction should be reduced. If the temperature is kept low and the alkali used is substantially the theoretical amount, the reaction can be continued for an hour or more without reducing the yield materially. Similarly, the procedure of adding the materials may also be varied. Thus, a solution of caustic soda may be added to an emulsion of hydrogen peroxide and a fatty acid chlorid, or both the hydrogen peroxide and caustic solution may be added simultancous- 1y to the fatty acid chlorid. The peroxides are sometimes solid, sometimes semisolid and sometimes liquid, de iending upon the average molecular weight and eutectic of the mixed peroxides.

lVe have found that a modification. of the above described process can be used to make per acids or per acid salts. It is necessary to change merely the amounts of the materials employed and the temperature and time of reaction. Thus, in order to produce fatty per acids, about 336 kilograms of 7 per cent hydrogen peroxide and 214-30 litres of 26.3 per cent caustic soda solution are mixed according to the method set forth above. \Vith these proportions of the materials employed, fatty per acids are formed. If it is desired to produce per acid salts of the fatty per acids, the amount of canstic solution used is the same as that given in the example for making fatty acid perox ides, but the hydrogen peroxide used must be more than double the amount used for the production of fatty acid peroxides. In forming the fatty acid per acids and per salts, the time of reaction and the agitation have to be somewhat increased over that necessary for. the production of fatty acid pen oxides. If per acid salts are formed, and the free per acids are desired, the filtrate is acidified and the free per acids are extracted or separated. In making the per acids or their salts, some fatty acid and diacyl peroxides are always formed. These are removed by filtration and the per acids or their salts are recovered from the filtrate. The fOl'Il'littiOH of per acid salts is easily recognized by nearly complete solution of the acid chlorid in the reacting mixture. Then this clear solution is acidified the oily layer of per acids, mixed. with a little fatty acid, separates out. Thus, the per acids obtained in this manner always contain some fatty acids. The yields obtained in the production of fatty per acids and per acid salts are not as great as in the production of fatty acid peroxides.

\Vhile the examples mention only a few fatty acids used in making the peroxides and poi-oxidized compounds, it is to be understood that the invention is not limited thereto but includes the peroxides or peroxy compounds made from any fatty acids or their derivatives having more than four carbon atoms. The invention also includes the peroxides or peroxy compounds of any acids that occur in natural fats and oils, or waxes. Acids similar to those mentioned above ocour in both animal and vegetable materials and waxes. Both types of fatty materials are intended to be included within the scope of our invention. The peroxides mentioned above appear to be more stable and less explosive than most of the peroxides heretofore known and consequently form a class by themselves among organic peroxides.

The term fatty acids is not to be restricted by its generally accepted meaning. It is here used to include all. homologues of acids that occur in natural fats and oils and waxes of both animal and vegetable origin. Thus used, the term naturally excludes the lower fatty acids, such as acetic, propionic, etc., but includes all acids such as caproic, lauric, stearic, 'oleic, etc. v

The term peroxy compound is used to include all organic derivatives of hydrogen peroxide, metallic or nonmetallic, such as acyl peroxides, per acids, per acid salts, whether simple or complex.

Although we have described the prcferred procedure of practicing our invention it is to be understood that changes may be made in the amounts of materials and the temperatures employed without departing from the spirit of the invention or the scope of the subjoined claims.

lVe claim:

1. The process of making fatty acid peroxides and peroxy compounds, which comprises treating fatty acid chlorids with a solution of an alkali metal peroxide.

2. The process of making fatty acid peroxides which comprises treating fatty acid chlorids with a solution of alkali metal peroxide, the amount of alkali metal peroxide, the amount of alkali metal therein being not more than substantially twice the chemical equivalent of the chlorine of the fatty acid chlorids used.

8. The process of making fatty acid peroxides which comprises treating fatty acid chlorids with a solution of alkali metal peroxide of a concentration not greater than 10 per cent.

4. The process of making fatty acid peroxides which comprises treating fatty acid chlorids with a solution of alkali metal peroxide of a concentration not greater than 10 per cent, at a temperature below 50 C.

5. The process of making fatty acid peroxides which comprises treating fatty acid chlorids with hydrogen peroxide in the presence of caustic alkali, the amount of such austic alkali being not greater than twice the chemical equivalent of the chlorine of the fatty acid chlorids used.

6. The process of making fatty acid peroxides which comprises treating fatty acid chlorids with hydrogen peroxide in the pres ence of caustic alkali, the amount of such caustic alkali being not greater than twice the chemical equivalent of the chlorine of the fatty acid chlorids used, and the concentration of such alkali in solution being not greater than 10 per cent.

7. The process of making fatty acid peroxides which comprises treating fatty acid chlorids with hydrogen peroxide in the presence of caustic alkali, the amount of such caustic alkali being not greater than twice the chemical equivalent of the chlorine of the fatty acid chlorids used, and the concentration of such alkali in solution being not greater than 10 per cent and at a reac tion temperature below 50 C.

8. As a new product, substantially stable and non-explosive, non-ozonide peroxy compounds made from acids that occur in 11atu- -ral fats, oils or waxes.

tures.

VILLIAM B. STODDARD. VAMAN R. KOKATNUR.

CERTIFICATE or CORRECTION.

PM No. 1,718,609. Granted June 25, 1929, to

WILLIAM B. STODDARD ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring'correction as follows: Page 3, line 4, claim 2,

strike out the words and comma "the amount of alkali metal peroxide,"; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 30th day of July, A. D. 1929.

M. J. Moore,

(Seal) Acting Commissioner of Patents. 

